Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Background of the Invention
Centrifuge screen baskets ordinarily are frusto-conical
with their larger their outer ends and, whether horizontally or
vertically rotatable, have a seal ring around an outer end and
depend on holding to a practical minimum clearance between that
ring and a surrounding stationary ring on the centrifuge machine
in which the basket is mounted for minimizing escape of fluid or
other material past the basket's outer end.
The concern of the present invention is an improvement in
centrifuge screen baskets for positively opposing leakage of
material around an outer end of a basket.
Summary of the Invention
The primary object of the present invention is to provide
an improved centrlfuge screen basket so constructed and arranged
as in operation to oppose with positive force escape of material
past an outer end of the basket.
Another object of the invention is to provide an Improved
centrifuge screen basket insertable through an opening and
rotatably mountably in a centrifuge machine,the basket having
about an outer end a cylindrical collar mounting a plurality of
circumferentially spaced impeller blades so tilted in the
direction of rotation of the basket as on rotation thereof to
produce between the basket ring and a surrounding ring on the
~ centrifuge machine an inward force or blast of air opposing and
! preventing escape of material past the basket's outer end.
An additional object of the invention is to provide a
centrifuge screen basket of the character described in the
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immediately preceding object, ~herein the impeller blades are
uniformly spaced and tilted forwardly in the direction of rotation
of the basket.
The foregoing and other objects and advantages of the
invention will appear hereafter in the detalled description, be
particularly pointed out in the appended claims 7 and be
illustrated in the accompanying drawings, in which:
Figure Description
Fig. 1 is a schematic vertical sectional view of a
centrifuge mounting for horizontal rotation and reciprocation a
preferred embodiment of the centrifuge basket of the present
invention;
Fig. 2 is a fragmentary vertical sectional view on an
enlarged scale of the so-numbered encircled portion of Fig. 1;
Fig. 3 is a bottom plan vie~ on a scale intermediate Figs.
1 and 2 showing the preferred embodiment of the basket and a
surrounding stationary ring in the centrifuge machine; and
Fig.4 is a side elevational view of the basket of Fig. 3
on the scale of that figure.
Detailed Description
Referring now in detail to the drawings in which like
reference characters designate like parts, the improved air sealed
centrifuge screen basket of the present invention is designed for
use in apparatus for centrifugally separating material and
specifically for use in centrifuge machines in which it is
impraotioal or imposrible to pre ent leakage or esoape of
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previously separated material past and remixing thereof beyond an
outer end of a basket in the machine. The improved basket is
particularly designed for use in a centrifuge machine in which the
basket is mounted for rotation about a horizontal axis and will be
so described as exemplary of the invention.
As typical of its use in centrifuges, the improved air
sealed centrifuge screen basket, designated as 1, has been
illustrated installed or mounted in a WEDAG vibrating screen-type
centrifuge or centrifuge machine 2. Suitably frusto-conical, the
screen basket 1 is mounted in the centrifuge 2 for rotation about
and oscillation or vibration on or along a horizontal axis. Both
types of motion are applied or imparted to the basket 1 by a drive
shaft 3 journaled in a housing 4 of the centrifuge 2, the shaft
having on an inner or front end a conveniently belt-driven drive
wheel or pulley 5 and being drivably engaged intermediate its ends
by a vibration unit 6. A drive motor (not shown) in the housing ~,
drivably connected to the drive wheel or pulley 5, drives the
l centrifuge 2.
j The illustrated centrifuge 2, has on the rear or outer
end of the shaft 3 a hub 7 concentrically mounting an imperforate,
inwardly flaring conical supporting or connecting member 8 having
as an integral or unitary inner end portion, a rib-reinforced
peripheral mounting flange g. In turn, the basket 1, for
installing or mounting in the centrifuge 2, has on its smaller
diameter front or inner end 10 an annular mounting disc or plate
11 fittable concentrically against and releasably attachable, as
J by bolting9 to the mounting flange 9.
~ Adapted to separate into components by deliquifying or
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classifying solid~liquid, solid-solid and even liquid-liquid
mixtures, the exemplary centrifuge 2 is particularly designed for
filtering or separating water from the particulate solids of a
coal or other slurry or solid-liquid mixtureO Both mounted on and
closed at its smaller inner end or bottom 10 by the conical
support member 8 to which lts mounting disc 11 is releasably
attached and preferably bolted, the basket 1 conveniently has the
slurry or other mixture fed to its inner end by a chute 12.
~nder the impetus of the centrifugal and vibrational
forces to which it is subjected in service, the slurry flows
outwardly along the screen 13 at the side 1~1 of the basket toward
the basket's larger outer end 15 and progressively has its liquid
and solid components separated by passing liquids through and
holding or retaining solids on tie rod-backed wedge or
wedge-shaped wires 16a preferably forming the internal screening
surface 16 of the screen. A dividing wall or partition 17,
substantially coplanar with the basket's outer end 15, has a
central opening or aperture 18 through which the basket is
received or inserted for installing or mounting it in the
centrifuge machine, the aperture having an inner edge 19 of larger
diameter than and radially spaced outwardly of the basket's outer
end. The wall 17 divides the centrlfuge 2 internally into front
and rear compartments 20 and 21 for receiving and temporarily
storing respectively the liquid and solid or other components
separated from the initial mixture.
The basket-receiving central opening 18 in the dividing
wall 17 and the basket itself in operative position are
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substantially concentric or coaxial with each other and the drive
shaft 3. However, because of manufacturing tolerances in the
basket 1 or the centrifuge machine 2 or both, it is practically
impossible, with the inner edge 19 of the opening 18 fixed, to
center the basket on the opening. It therefore is the practice to
provide especially horizontal or horizontal axis centrifuge
machines with a cylindrical machine seal ring 22 mountable on the
dividing wall 17 inside the opening 18. Horizontally directed or
vertically disposed, the machine seal ring 22 is inserted in the
opening 18 between or intermediate the opening's inner edge 19 and
a confronting, horizontally disposed cylindrical seal collar or
ring 23 on, about, surrounding or encircling the outer end portion
of the basket. With an integral peripheral flange 2L~ overlapping
and releasably attached, as by bolting, to the wall 17, the
machine seal ring 22 is mounted for limited movement, adjustment
or shifting in any direction on or parallel to the wall. The
centrifuge machine 2 thus can compensate for manufacturing
tolerances in itself or a basket by adjusting the machine seal
ring 22 relative to the wall 17 to center the ring on a basket
mounted in the machine.
While the lateral adjustability of the machine seal ring
22 relative to the wall 17 enables the ring to be centered on any
basket installed in the centrifuge machine, the centering does not
prevent leakage of water or other screened materi.al between the : .
machine ring 22 and the basket ring 23. Nor does the terming of
the rings "seal rings" denote that they actually perform that
function, since, to accommodate relative rotation of the basket,
the fit between the rings must be fairly loose, with the radial
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spacing or clearance between the rings suitably on the order of at
least about 1/8" (0.317 cm).
Conventionally, a horizontally rotatable screen basket has
around its outer end an annular outer end plate 25, to the inside
of which the outer ends of the wedge-shaped screen wires 15 are
fixed. Again conventionally, the outer end plate 25 surmounts and
has the same outside diameter as the basket seal ring 23 which it
connects by welding to the rest of the basket. Unconventionally,
in the improved basket of the present invention, the basket seal
ring 23, although still surmounted by and welded to the outer end
p].ate 25, is inset radially relative to or of less diameter than
the end plate and mounts therebelow on its side 26 a plurality of
radially outstanding, circumferentially spaced airfoil impeller
blades 27, each tilted forwardly in the direction of rotation of
the basket. Projecting radially beyond the end plate 25 and
desirably extending the full width of both basket and machine
rings 22 and 23, the blades 27 preferably are radially spaced from
the machine ring by about 1/8" (0.317 cm~ and are uniformly tilted
and cicumferentially spaced, suitably with a forward tilt of about
30 degrees and a spacing of about 10 degrees. The blades need not
be of a particular airfoil shape and may simply be 2" (5.08 cm)
lengths cut from 3/8" (.951 cm) square stainless steel bar stock.
In any case, since a basket is always rotating when it is
separating a mixture into components, whenever screened material
might otherwise escape between the rings 22 and 23, the escape is
always blocked or prevented by the opposing positive forward air
blast or force generated by the rotating blades 27 and there is
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no remixing of previously separated components in the rear
compartment 21 beyond the basket.
From the above detailed desccription it, will be apparent
that there has been provided an improved centrifuge screen basket
mounting around an outer end airfoil blades tilted forwardly in
the direction of rotation of the basket for generating on rotation
a positive force of air opposing escape around and remixing beyond
an end of a basket of a previously separated component. It should
be understood that the described and disclosed embodiment is
l~ merely exemplary of the invention and that all modifications are
intended to be included that do not depart from the spirit of the
invention and the scope of the appended claims.
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